The sun: what it is and what is its function in the Solar System

The interstellar Universe is immense, humanity has only been able to sketch its extension. However, we are not even close to knowing its limits and we are constantly looking for answers about it. But within the immense cosmos, within the Milky Way, lies our Solar System, the cosmic neighborhood that inhabits the Earth and whose main star is the Sun, which plays an important role in it.

The Sun is the main star of the Solar System. It is a huge star, with 1.4 million kilometers in diameter, it is so big that it could house 109 planets just on its surface. And it is to be assumed that the main energy source of the entire system plays a primary role. It gives light, heat and holds together the planets revolving around it. In addition, it is responsible for life on planet Earth. Its energy and the set of characteristics of our planet, favored the ideal conditions for the emergence of life on Earth some 4 billion years ago.

And although compared to the other stars in the cosmos, the Sun is not that big, for the Solar System it is its main agent. Thanks to its large amount of mass, it generates a curvature in time-space that causes the planets to revolve around it.

What is the Sun made of?

Almost entirely the Sun is made up of two gases: hydrogen and helium. And to put its size in perspective, its mass represents 99.8% of the total mass of the Solar System. Being a star, the Sun is a collection of gases in constant activity that reach exorbitant temperatures. On its surface, the temperature is around 5,500°C. But inside, it rises exponentially to reach 15,000,000°C.

But not all of the Sun is made up uniformly, like the Earth, it is structured in layers. In its center the nucleus burns, where the temperatures are enormous and it is where the fusion explosions that produce its heat are gestated. Although due to the characteristics of its gravity, the energy produced in the center takes about a million years to emerge to the surface.

It is followed by the radiant zone that is composed mainly of plasma, that is, of ionized gases. Next are the convective zone. Then the photosphere, which is where the visible light of the largest body is emitted, is considered the solar surface and is where sunspots appear. Then the outer layers, the chromosphere and finally the solar corona are superimposed. Together, all these and their intrinsic characteristics generate the energy that feeds the Solar System.

it is not eternal

Astronomers calculate that the formation of the Sun occurred about 4.57 billion years ago. And although for the ephemeral human existence, the times of cosmological history are immense, the Sun also has an expiration date. Scientists estimate that this giant star has already lived half of its existence, so it has about 5,000 million more years to go.

In this period, it will lose its current appearance, that is, it will shine brighter but the heat will be less. It will then become a red giant star, reaching a hundred times its present size and devouring Earth and other planets in its path. Thus, it will burn as a red giant for another billion years to finally explode as a white dwarf the size of our planet.

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